This application is based on Japanese Patent Application No. 9-195116, which was filed on Jul. 4, 1997, and which is incorporated by reference in its entirety herein.
1. Field of the Invention
The present invention relates to complex electronic components, and more particularly, to a complex electronic component having a structure in which a plurality of devices, such as an inductor, a resistor, and a capacitor, are disposed in ceramic.
2. Description of the Related Art
As a conventional noise-canceling interface (noise-canceling filter device) used in an interface line of an office automation unit such as a computer, a complex inductor component (complex electronic component) such as that shown in FIG. 7 is used. This integrally-baked complex inductor component is formed in order to reduce a space required for mounting to allow high-density mounting such that a plurality of inductors 2 having a coil shape and serving as inner electrode layers 12 are disposed in line on the same plane inside a laminated member 1 formed by laminating magnetic ceramic (ferrite) layers, and a plurality of outer electrodes 3 which are electrically connected to the inductors 2 through lead electrodes 13 are disposed outside the laminated member 1.
When a high voltage is applied to each inductor of the conventional complex inductor component, however, migration of the inner electrodes may occur along a laminated surface or insulation resistance may decrease, due to at least the following reasons:
1) short distances between the inductors;
2) arrangement of the inductors on the same magnetic ceramic (ferrite) layer; and
3) not-very-high insulation capability, e.g., an insulation resistance of about 109 to 1010 xcexa9xc2x7cm in magnetic ceramic (ferrite).
It is an object of the present invention to provide a complex electronic component which can prevent migration of the inner electrodes and can provide a reduction in insulation resistance and also has a good insulation reliability between devices.
The foregoing objects and others are achieved according to one aspect of the present invention through the provision of a complex electronic component including: a plurality of devices disposed in parallel in magnetic ceramic; and an insulating member disposed between adjacent devices to enhance insulation therebetween.
Since the insulating member is disposed between adjacent devices, insulation between the devices is enhanced, and migration of an inner electrode and a reduction in insulation resistance are prevented. Insulation reliability between devices is also increased.
The foregoing objects and others are also achieved according to another aspect of the present invention through the provision of a complex electronic component including: a plurality of devices disposed in parallel in a laminated member formed by laminating a magnetic ceramic layer and an inner electrode constituting a device, adjacent devices among the plurality of devices being disposed on different planes inside the laminated member; and an insulating member disposed at least at a part of an intermediate layer positioned between the adjacent devices in the lamination direction to enhance insulation between the adjacent devices.
Since the adjacent devices among the plurality of devices are disposed on different planes inside the laminated member, migration of an inner electrode is even more unlikely to occur and a reduction in insulation resistance can be more effectively prevented. Since the insulating member is disposed at least at a part of an intermediate layer, positioned between the adjacent devices in the lamination direction, insulation reliability between devices is increased.
In the complex electronic component, the insulating member may be a wall-shaped insulating member which is formed by laminating insulating elements between the adjacent devices. The wall shaped insulating member also partitions zones where the adjacent devices are disposed.
Since insulating elements are laminated between the adjacent devices to form a wall-shaped insulating member which partitions zones where the adjacent devices are disposed, migration of an inner electrode and a reduction in insulation resistance are prevented. Insulation between the adjacent devices is further enhanced. Insulation reliability is substantially increased.
The wall-shaped insulating member can be easily formed, for example, by laminating, when the device is formed, ceramic green sheets on which an insulating pattern is disposed.
In the present invention, the wall-shaped insulating member is a broad-concept term and includes one formed by laminating a plurality of insulating layers through ceramic green sheets, which has gaps, and one having a wall without gaps. No special limitation is applied to the wall-shaped insulating member in terms of its shape and manufacturing method.
In the complex electronic component, the magnetic ceramic may have an insulation resistance of approximately 109 to 1010 xcexa9xc2x7cm. When magnetic ceramic or dielectric ceramic having an insulation resistance of approximately 109 to 1010 xcexa9xc2x7cm is used, a sufficient insulation reliability is ensured. A ceramic material can be selected from a broad class of materials, and a complex electronic component having the desired characteristics can be obtained.
With various electric characteristics being taken into consideration, magnetic ceramic or dielectric ceramic having an insulation resistance of approximately 109 to 1010 xcexa9xc2x7cm, which is not sufficiently large, is preferred in some cases. In such a case, when the present invention is applied, migration of an inner electrode and a reduction in insulation resistance are prevented. Insulation reliability between devices is increased. As ceramic having an insulation resistance of approximately 109 to 1010 xcexa9xc2x7cm, for example, ferrite or like material can be used. The present invention can also be applied to a case in which a material other than the above is used.
In the complex electronic component, the insulating member may have an insulation resistance of approximately 1012 xcexa9xc2x7cm or more. When an insulating member having an insulation resistance of approximately 1012 xcexa9xc2x7cm or more is used, insulation between devices is enhanced. As an insulating member having an insulation resistance of 1012 xcexa9xc2x7cm or more, glass including at least one selected from a group consisting of B, Zn, Ca, Al, and Si, or alumina can be used. Other materials can also be used.
In the complex electronic component, the plurality of devices may include at least one device selected from the group consisting of an inductor, a resistor, and a capacitor, for example. In this case, migration of an inner electrode and a reduction in insulation resistance are prevented, and insulation reliability is increased.
When a magnetic ceramic layer is used as a ceramic layer, magnetic ceramic layers and inner electrode layers are alternately laminated, and each inner electrode is electrically connected to each other to form coil-shaped inductors, a compact complex inductor component having a good insulation reliability between the inductors is obtained, without migration of the inner electrodes or a reduction in insulation resistance.
When a magnetic ceramic layer is used as a ceramic layer, and magnetic ceramic layers and inner electrode layers are alternately laminated to form capacitors in the ceramic, a compact complex capacitor component having a good insulation reliability between the capacitors is obtained, without migration of the inner electrodes or a reduction in insulation resistance. In the same way, a resistor can be formed in ceramic.
In a complex electronic component, two devices or more selected from a group consisting of an inductor, a resistor, and a capacitor can also be disposed in ceramic in a combination.